Policy circumvention

Note that we do not provide IPv6 connectivity to locations where the IPv6 tunnel would
circumvent a local policy formed by for instance a firewall.
Most corporate networks forbid forms of tunneling as this would open a channel over
which an attack into their corporate network could take place as it bypasses the
policies implemented in their firewalls.
If you are in such a situation, don't try to circumvent your administrators policy
but talk to them and try and get IPv6 connectivity setup together with them according
to their policies, it is their network afterall, not yours.

Network administrators can easily block the usage of SixXS by blocking the above ports.